U.S. patent application number 11/773243 was filed with the patent office on 2008-02-07 for single or multiple route map matching apparatus for navigation service and method thereof.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Kyong-Joon Chun, Eun-Hee LEE, Young-Khon Moon.
Application Number | 20080033634 11/773243 |
Document ID | / |
Family ID | 27725827 |
Filed Date | 2008-02-07 |
United States Patent
Application |
20080033634 |
Kind Code |
A1 |
LEE; Eun-Hee ; et
al. |
February 7, 2008 |
SINGLE OR MULTIPLE ROUTE MAP MATCHING APPARATUS FOR NAVIGATION
SERVICE AND METHOD THEREOF
Abstract
Disclosed is a single or multi-route map matching apparatus in a
system which provides a navigation service via a mobile
communication terminal. The map matching apparatus comprises: an
information center for calculating an optimum route to a
destination inputted by a user based upon a present location of the
mobile communication terminal, and generating a format of route
data based upon the calculated optimum route; and an Intelligent
Transportation System (ITS) terminal for detecting the present
location of the mobile terminal to generate location data,
processing the route data, performing map matching based upon the
location data to determine whether the user travels on a given
route or departs from the route, and performing road guidance based
upon a result of the map matching.
Inventors: |
LEE; Eun-Hee;
(Kwangmyong-shi, KR) ; Chun; Kyong-Joon; (Seoul,
KR) ; Moon; Young-Khon; (Suwon-shi, KR) |
Correspondence
Address: |
THE FARRELL LAW FIRM, P.C.
333 EARLE OVINGTON BOULEVARD
SUITE 701
UNIONDALE
NY
11553
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
27725827 |
Appl. No.: |
11/773243 |
Filed: |
July 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10371062 |
Feb 20, 2003 |
|
|
|
11773243 |
Jul 3, 2007 |
|
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Current U.S.
Class: |
701/533 |
Current CPC
Class: |
G01C 21/3415 20130101;
G01C 21/30 20130101 |
Class at
Publication: |
701/201 |
International
Class: |
G01C 21/30 20060101
G01C021/30; G01C 21/34 20060101 G01C021/34 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 27, 2002 |
KR |
2002-10692 |
Claims
1-6. (canceled)
7. A single or multi-route map matching method for performing a
navigation service via a mobile communication terminal, the map
matching method comprising: (a) a first stage of transferring, by
the mobile communication terminal, information about a destination
inputted by a user into an information center; (b) a second stage
wherein the information center performs: a first step of
determining a present location and searching a destination, a
second step of performing route calculation by setting a gateway, a
third step of generating a RGI format data by generating a basic
RGI data, and a fourth step of transmitting the generated RGI
format data into the mobile communication terminal; (c) a third
stage of transmitting, by the mobile communication terminal, the
RGI data transmitted from the information center into the ITS
terminal; and (d) a fourth stage wherein the ITS terminal performs:
a first step of determining a present location of a user, a second
step of searching for a matching road through RGI data patching and
map matching to judge whether the user departs from a route, a
third step of generating route guidance information as a result of
the judging step, and a fourth step of transmitting the generated
route guidance information into the mobile communication terminal,
determining whether the user arrives at the destination, and if
having not arrived, returning to the first step of present location
determination, and wherein the mobile communication terminal
displays the route guidance information received from the ITS
terminal.
8. A single or multi-route map matching method in accordance with
claim 7, wherein the information center performs route calculation
by setting a gateway, generating multiple routes with respect to
the set gateway, and generating congested intersection information
in the second step of the second stage.
9. (canceled)
Description
PRIORITY
[0001] This application claims priority to an application entitled
"Single or Multiple Route Map Matching Apparatus for Navigation
Service and Method Thereof" filed in the Korean Industrial Property
Office on Feb. 27, 2002 and assigned Serial No. 2002-10692, the
contents of which are hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a navigation system, and
more particularly, to a map matching apparatus and method for a
single route or multiple routes.
[0004] 2. Description of the Related Art
[0005] A vehicle navigation service has a primary purpose of
guiding a user to a desired destination via an in-vehicle mobile
communication terminal and a navigation terminal functioning as a
handsfree kit. In such a vehicle navigation service, a database
(e.g., comprising a map) is needed to determine a present location
of a vehicle or select a route. According to the current trend, the
database is provided from a remote information center to the user
rather than stored in the terminal. In a navigation system which
provides the navigation service by merely referring to an optimum
route obtained through calculation of data including traffic
information in the information center, the user must re-access the
information center to acquire a new route whenever he/she departs
from a given route. In practice, it is possible that the user, by
intention or mistake, does not ultimately travel along the provided
optimum route. This will be treated as departure from the given
route, and so the user must re-access the information center,
thereby creating a burden on communication resources and the burden
of the cost of the re-access.
SUMMARY OF THE INVENTION
[0006] The present invention has been made to solve the foregoing
problems and it is therefore an object of the present invention to
provide a map matching apparatus and method for a single route or
multiple routes, which allow travel along an optimum route.
[0007] According to one aspect of the invention to obtain the above
objects, a single or multiple route map matching apparatus, in a
system which provides a navigation service via a mobile
communication terminal, comprises: an information center for
calculating an optimum route to a destination inputted by a user
based upon a present location of the mobile communication terminal,
and generating a format of route data based upon the calculated
optimum route; and an Intelligent Transportation System (ITS)
terminal for detecting the present location of the mobile terminal
to generate location data, processing the route data, performing
map matching based upon the location data to determine whether the
user travels on a given route or departs from the route, and
performing road guidance based upon a result of the map
matching.
[0008] According to another aspect of the invention to obtain the
above objects, a single or multi-route map matching method for
performing a navigation service via a mobile communication
terminal, the map matching method comprising:
[0009] (a) a first stage of transferring, by the mobile
communication terminal, information about a destination inputted by
a user into an information center;
[0010] (b) a second stage wherein the information center performs:
[0011] a first step of determining a present location and searching
a destination, [0012] a second step of performing route calculation
by setting a gateway, generating multiple routes in respect to the
set gateway and generating congested intersection information,
[0013] a third step of generating an RGI format data by generating
a basic RGI data, expanding a multi-route data, and adding the
congested intersection information from the route calculation step
to the RGI data, and [0014] a fourth step of transmitting the
generated RGI format data into the mobile communication
terminal;
[0015] (c) a third stage of transmitting, by the mobile
communication terminal, the RGI (Route Guidance Instruction) data
transmitted from the information center into the ITS terminal;
and
[0016] (d) a fourth stage wherein the ITS terminal performs: [0017]
a first step of determining a present location of a user, [0018] a
second step of searching for a matching road through RGI data
patching and map matching to judge whether the user departs from a
route, [0019] a third step of generating route guidance information
as a result of the judging step, and [0020] a fourth step of
transmitting the generated route guidance information into the
mobile communication terminal, determining whether the user arrives
at the destination, and if having not arrived, returning to the
first step of present location determination, and wherein the
mobile communication terminal displays the route guidance
information received from the ITS terminal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0022] FIG. 1 illustrates a construction of a navigation system to
which the invention is applied;
[0023] FIG. 2 is a flowchart of a map matching process on multiple
routes for a vehicle navigation service according to a preferred
embodiment of the invention;
[0024] FIG. 3 is a map illustrating an example of multiple routes
devised according to the present invention;
[0025] FIG. 4A is a diagram illustrating an example of a
construction of RGI data.
[0026] FIG. 4B is a diagram illustrating map matching of the
invention;
[0027] FIG. 5 is a flowchart illustrating an operational process
for patching initial RGI data during map matching of an ITS
terminal according to the preferred embodiment of the invention;
and
[0028] FIG. 6 is a flowchart illustrating an operational process
for patching subsequent RGI data during map matching of the ITS
terminal according to the preferred embodiment of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] The following detailed description will present a preferred
embodiment of the invention in reference to the accompanying
drawings, in which the same reference numerals are used throughout
the different drawings to designate the same or similar components.
Specific features such as detailed circuit components are disclosed
in the following specification to help more general understanding
of the invention, and it will be apparent to those skilled in the
art that the invention can be made without these specific features.
Furthermore, well-known functions or constructions will not be
described in detail since they would unnecessarily obscure the
understanding of the invention.
[0030] FIG. 1 illustrates a construction of a navigation system in
accordance with the invention.
[0031] The navigation system includes an information center 100, a
radio network 200, a mobile communication terminal 300 and an
Intelligent Transportation System (ITS) terminal 400.
[0032] The information center 100 stores map data and realtime
traffic information. At the request of the mobile communication
terminal 300 for a navigation function, the information center 100
refers to the map data and the realtime traffic information to
generate navigation information corresponding to the request, and
provides the generated navigation information to the mobile
communication terminal 300 via the radio network 200. For example,
when the mobile communication terminal 300 requests guidance to an
optimum route from a present location to a destination, the
information center 100 refers to the map data and the realtime
traffic information to generate guidance information for the
optimum route from the present location to the destination.
[0033] The radio network 200 is a medium for information
transmission between the information center 100 and the mobile
communication terminal 300. Available examples of the radio network
200 may include a communication system based upon the currently
popular Personal Communication System (PCS) and a digital cellular
system based upon the IS-95A, -95B or -95C system. The radio
network 200 may also utilize Code Division Multiple Access (CDMA)
digital cellular systems such as the International Mobile
Telecommunications 2000 (IMT-2000) and the Universal Mobile
Telecommunication Systems (UMTS), which are being widely researched
at present.
[0034] The mobile communication terminal 300 operates not only in a
mode for providing a voice communication service but also in a
navigation mode for supporting the navigation function. In the
navigation mode, the mobile communication terminal 300 accesses the
radio network 200 to receive various navigation information
provided from the information center 100, and cooperates with the
ITS terminal 400 to provide a user with the received navigation
information.
[0035] In the navigation mode, the user can set the present
location of a vehicle and a destination via the mobile
communication terminal 300 in order to request the guidance of the
optimum travel route from the information center 100. In this
manner, the user may be provided with guidance regarding the
optimum travel route from the information center 100 according to a
typical navigation function. The user can make audio or text input
to set the destination expressed as facility name, district
category, administrative district name, town, zip code, street
address, telephone number or longitude and latitude. In the
navigation mode, the user may be also provided with traffic
information (e.g., front area situation in traveling, downtown
information, road information, highway information, information in
respect to favorite places) from the information center 100.
Further, the user can access the information center 100 via the
mobile communication terminal 300 to search for nearby facilities,
e.g., gas station, garage, bank, hospital, pharmacy and so on.
[0036] The mobile communication terminal 300 cooperates with the
ITS terminal 400 to provide the received route guidance information
to the user in a visual and/or audible manner. When visually
provided to the user, the route guidance information can be shown
on a display section of the mobile communication terminal 300 or
via a dedicated display unit which is externally mounted and
separately linked to the terminal 300. Also, when audibly provided,
the route guidance information is sent to the outside via a speaker
mounted on the mobile communication terminal 300 or the ITS
terminal 400.
[0037] Describing a general construction of the ITS terminal 400, a
Global Positioning System (GPS) engine 420 receives radio waves via
an antenna 418 from a plurality of artificial satellites belonging
to the GPS. A gyro-sensor 414 and a velocity sensor 416 constitute
a sensor block, which detects the angle of rotation and the
velocity of a vehicle, respectively, via the gyro-sensor 414 and
the velocity sensor 416. An RGI data storage block 550 stores map
data, and available examples thereof may include SRAM. A map
matching block 570 accepts RGI data from the RGI data processing
block 560 and present location data from a processor 410 to perform
a map matching process.
[0038] FIG. 2 is a flowchart illustrating a map matching process
for a vehicle navigation service according to a preferred
embodiment of the invention.
[0039] The operation of the information center will be described as
follows:
[0040] In step 10A, the information center determines the present
location of a user, and searches for the destination of the
user.
[0041] That is, the information center determines points on a map
to which the present location and the destination of the user
correspond. The present location is searched for based upon present
location data (input by user at mobile terminal 300, or transmitted
from GPS engine 420 through mobile terminal 300) and heading
information of a vehicle transmitted from the ITS terminal, in
which the information center can calculate a route while giving
priority consideration to the direction of advancement of the
vehicle or without consideration to the direction of the vehicle.
Based upon a name or other destination type data inputted by the
user, the information center searches for the location of the
corresponding name and a road matching thereto in a facility
information database of the information center in order to find the
destination. A nearby road is matched if the correspondent facility
is distant from roads in the database.
[0042] In step 11A, the information center performs route
calculation by setting gateways (e.g. specific intersections),
generating multiple routes with respect to the set gateways, and
generating congested route and/or intersection information, in
which the traffic information is reflected.
[0043] The information center matches the found present location
and the destination road to links on route calculation data. The
information center performs route searching from the present
location to the destination road. The route search is performed to
find a route between the present location and the destination
consuming the lowest value based upon a value ascribed to each of
the links in the route calculation data. With respect to an area
where traffic information is provided, the information center
calculates the value thereof based upon the received traffic
information rather than the route calculation data. The route
search reflects the difficulty of traversing each intersection, for
example. Also, the route search reflects a weighting of road
classification (highway versus local roadway, for example),
intersection and turning type. For each candidate route, the route
search repeats the steps of storing the value between roads, which
have been found thus far, and a next road connecting the route, and
calculates the value of the connected next road based upon the road
consuming the lowest value among those which have been calculated
so far. The information center can search all routes from the
present location to the destination by using the route search.
[0044] In the gateway setting, the information center searches a
congested intersection database to select n number of points about
the congested intersections where the user may readily depart from
the given route or sections where traffic flow changes frequently,
potentially causing the user to intentionally depart from the given
route. The gateway sections are restricted within a range of
.alpha.% with respect to the whole number of routes since they are
also limited by the size and capacity of the entire RGI data. In
the route search, if sections of the route pass by those
intersections stored in the congested intersection database and are
within the range of .alpha.% with respect to the estimated whole
number of routes, they are registered as gateways, and the
congested intersections are separately stored. Separate storage of
the congested intersections adds information for partial route
extraction and rough maps around the congested intersections to the
RGI data as separate data which can be displayed on the mobile
communication terminal. Each of the intersections from the RGI data
having the rough route data is further provided with an offset for
showing whether the intersection has a map of a correspondent
congested intersection and allowing access to the data.
[0045] Further, the information center must have a congested
intersection database or a database storing information of
intersections which are congested or have a large variation in
traffic flow. The congested intersection database contains
nation-wide intersection names, road classifications, link
information (e.g., highway or route numbers, attributes, etc.),
point information, etc. based upon regions. A route calculation
utilizes the congested intersection database.
[0046] The congested intersection database contains information
which is usable in matching congested intersections in calculation
and configuration information of each congested intersection (e.g.
line configuration of the intersections).
[0047] Upon completion of the route search, the information center
extracts partial routes generated as end gateways respectively from
the present location and the destination, and stores the extracted
partial routes. This allows the multiple routes to be so devised
that upper and lower sub-routes are stored with both ends
functioning as the end gateways.
[0048] FIG. 3 is a map illustrating multiple routes devised
according to the invention.
[0049] The reference number 120 designates a present position of a
mobile body (e.g. vehicle), 140 designates a gateway, 160
designates a first sub-route, 165 designates a second sub-route.
The routes 160 and 165 are set as sub-routes rather than an optimum
route since they are both congested owing to a large volume of
traffic. The reference number 180 designates the optimum route, and
200 designates a destination.
[0050] Route search can select not only a road on the optimum route
but also other roads connected to the optimum route. Although
excluded from the optimum route, those roads set as gateways can be
maintained with a certain degree of connectivity.
[0051] Referring to FIG. 2 again, the information center generates
the RGI format data using the optimum route in step 12A.
[0052] To be specific, the information center primarily generates
the RGI data, expands multiple route RGI data, and then adds the
congested intersection information obtained from the route
calculation to the RGI data.
[0053] The multiple route and congested intersection data are
utilized to minimize drawbacks of a conventional single route
(e.g., upon departure from the given route, the user must re-access
the information center to download a new route again, thereby
incurring additional costs for re-access and related service) while
enhancing expansibility and flexibility of the RGI data.
[0054] The information center generates RGI data from the multiple
routes passing by a gateway via the sub-routes from the gateway on
the optimum route, and stores offsets into RGI items corresponding
to the gateway. When several sub-routes are associated with one
gateway, each of the sub-routes stores an offset of the next
sub-route toward the RGI so that following of the offsets allows
access to several sub-routes. This constitutes an annular offset
structure in which continuous following of the offsets returns to
the original optimum route.
[0055] The information center generates an offset between the last
portion of each sub-route of the gateway and an overlapped portion
of the optimum route in the same manner as the offset in the
gateway.
[0056] In step 13A, the information center transmits the generated
RGI format data into the mobile communication terminal (S2).
[0057] Hereinafter, the operation of the mobile communication
terminal will be described.
[0058] In step 21B, the user inputs his/her destination into the
mobile communication terminal. Although this embodiment assumes
that the destination is inputted into the mobile communication
terminal, the destination can be also inputted into the ITS
terminal, which transmits the destination into the mobile
communication terminal.
[0059] In step 22B, the inputted destination information is
transmitted into the information center (S1).
[0060] In step 23B, the RGI data transmitted from the information
center (step S2) are transmitted into the ITS terminal (Step
S3).
[0061] In step 24B and 25B, the mobile terminal receives route
guidance information from the ITS terminal (S4) and displays the
route guidance information until the vehicle arrives at the
destination. The ITS terminal provides guidance of a next
intersection, distance or time information up to the destination,
etc. in a turn-by-turn mode.
[0062] Hereinafter the operation of the ITS terminal will be
described as follows:
[0063] In step 31C, the ITS terminal determines the present
location of the user. The present location of the user is
calculated based upon information obtained from various location
information sensors (e.g., GPS, gyro-sensor and acceleration
sensor).
[0064] In step 32C, the ITS terminal searches for a matching road
to judge whether the vehicle departs from the route. The ITS
terminal searches for a matching road in the RGI data (i.e., a data
format for road and route guidance) for the present location of the
user. If any matching road is found, it is judged that the vehicle
has departed from the route.
[0065] Hereinafter the RGI data patch will be described in more
detail as follows:
[0066] Map information in conventional navigation data is
constituted of a certain amount of road data. For the purpose of
accessing all of the road data corresponding to each area, the
corresponding area is searched for in an area management table so
that raw data can be used, in which the area and the road data each
are unique. The road data are searched to match the location of the
user on the road, in which the road data are generally searched
within a specific area about the present location and in respect to
each zone. As the user travels changing the present location area,
the area of search list is updated.
[0067] The navigation system used in the embodiment of the
invention is inexpensive since it does not internally install map
information. The information center provides the navigation system
with the RGI data in a simple form used in map matching and route
guidance for the user traveling to the destination, and thus the
navigation system realizes a basic function of navigation.
[0068] The RGI data are sequentially made based upon specific zones
which are the areas in the route between the present location and
the destination. The route can repeatedly enter and exit a specific
district in a zigzag manner. The user may discuss a policy of
effective patching instead of patching all the data every time in
data patching, e.g., he/she may drive in a different manner where P
turn is needed at a boundary of districts. That is, the same area
can be irregularly repeated. According to an aspect of this system,
through the entry point, the user can enter an intermediate point
of the RGI data and then be guided by the system rather than
traveling from the starting point of the RGI data. Also, the user
may depart from the route according to the setting of the user even
though he/she is traveling under the normal route guidance after
entry, in which case the user may re-enter the original route
through entry point guidance. Therefore, it is necessary to patch
the data in a manner capable of coping with the above
situations.
[0069] 1) If the user fails to enter a given route, the RGI data
are searched for in the initial portion until an area identical
with the present location is found. If an area other than an
adjacent area (e.g., within .+-.1 of the reference index of the
present location) is found, the search is stopped.
[0070] 2) If an area corresponding to the present location varies
from the determined route, a data patch algorithm is processed. The
patch algorithm is used to focus on a smaller section of the entire
route for management, from the current location of the vehicle
through adjacent areas of a predetermined size and location
("patches") through which the route runs.
[0071] 3) After the initial data patch is determined, an index of
the existing area list is updated on the basis of the present
location area.
[0072] 4) An area list of new RGI data is started from an area
which was last searched in the previously searched RGI data.
[0073] 5) After searching the area corresponding to the present
area, search and management are performed only to adjacent areas
(within .+-.1 of the reference index of the present location).
[0074] Next, the map matching will be described in detail as
follows:
[0075] The map matching calculates whether the user travels on a
corresponding road on a single route, and the actual location of
the user in a multiple route section.
[0076] 1) The present location road of the user is searched for
using road data in the final patched area list (within .+-.1 of the
reference index of the present location). The matching adopts
direction and position values of the vehicle together with a map
matching algorithm through road data matching. (The map matching
algorithm will not be discussed herein.)
[0077] 2) In the multiple routes, an area list of each of the
routes is separately managed, and used in map matching when the
user approaches one of the multiple routes.
[0078] FIG. 4A is an example diagram illustrating a construction of
RGI data in detail.
[0079] Numbers shown in FIG. 4A are used for indicating areas
(hereinafter will be referred to as id), for the sake of
convenience. As shown in FIG. 4A, there are four ids, and a vehicle
moves through three ids among the four ids. A solid line in id 3
designates link 1 and it indicates a locus which the vehicle moves
in id 3. A dotted line in id 1 designates link 2 and it indicates a
locus which the vehicle moves in id 1. A dotted line in id 4
designates link 4 and it indicates a locus which the vehicle moves
in id 4. Each link is indicated with a solid line or dotted line,
solely for clarity in FIG. 4A.
[0080] According to FIG. 4A, the vehicle starts from id 3 and
travels to id 1, id 3, and id 4. Therefore, the RGI data generated
includes the traveled areas as sub-data, i.e., four sub-data items
in this case. Each sub-data item is comprised of a pair of id
information and link information. In FIG. 4A, the four sub-data are
comprised of (id 3, link 1), (id 1, link 2), (id 3, link 3), (id 4,
link 4) according to sequential traveling of the vehicle, wherein
the link information includes generic characters of a road such as
a highway, a fan shape, or a crossroads.
[0081] When the vehicle moves to another area, ITS terminal 400
performs an operation for determining RGI data and the operation
corresponds to step 32c in FIG. 2.
[0082] FIG. 4B is a diagram illustrating the map matching of the
invention. The numbers 1 to 16 in FIG. 4B indicate ids and the
alphabet a to h indicate vehicle position. If the vehicle is
located in id 13, ids that are searched to include RGI data and
that correspond to within the limits of peripheral index .+-.1 from
an area where the vehicle is currently located are found to be ids
13, 14 and 10. Thereafter, if the vehicle moves to b of id 14, RGI
data is searched for within the limits of peripheral index .+-.1.
Thus, the ids are "patched" as the vehicle moves along the route.
If the vehicle is located in b of id 14, RGI data is searched for
in id 11 which is a new id with respect to the previously searched
ids, because RGI data is already searched in three ids, i.e., ids
13, 14, and 10 corresponding to peripheral index .+-.1 centering on
a of id 13.
[0083] The following description is another example illustrating
map matching when the vehicle travels not from id 13 but from id
17, which is off the route. Starting from id 17 (which is an area
directly below id 13, even though not shown in FIG. 4B), whole RGI
areas will be searched (in the order of 13, 14, 10, 11, 10', 6, 7,
8 and 4 in the drawing) since the current location does not
correspond to one of the id areas. In this case, id 13 and id 14
are added to an area list, and when the vehicle moves into id 13,
the search will continue with id 10 as in the search above.
[0084] When the vehicle travels along a through h changing its
location with respect to the determined route, the following
operations will be performed: Hereinafter a backup area is
considered as a previously patched id area in the foregoing phase
and will be updated with indices (*, *) only. A reference area
means an area where the vehicle is located, that is, having an
index (0, 0). A new area is newly added to the area list, after
being searched from the area of current location.
[0085] The RGI data are generated in the information center, as a
format established for performing map matching and route guidance
in the ITS terminal. The RGI data may not include other surrounding
road information since the RGI data are applied to the calculated
route between the present position of the vehicle and the
destination. Therefore, the RGI data are not generated for all ids,
but generated in sequence according to an advancing direction of
the calculated route (e.g., in the order of 13, 14, 10, 11, 10', 6,
7, 8 and 4), and contain links and node information.
[0086] Traveling of the vehicle generates new location values, and
locations of the vehicle are determined based upon the location
values in the RGI data. That is, the RGI data are used whenever new
location data are generated. Location n in the nth area indicates
the position in the RGI data in the nth area. When a vehicle moves
into a new id area, RGI data is searched for in nearby areas
(within peripheral index .+-.1) that have not yet been
searched.
[0087] The reference area means an area where the vehicle is
currently located. The previously searched areas have their indices
changed to the backup areas on the basis of the present location of
the vehicle. The previously searched areas are treated as backup
areas, in which the indices are changed based upon the present
location of the vehicle. The RGI data in use for calculation
include only those data such as links, nodes and so on belonging to
a range of indices (.+-.1, .+-.1) of where the vehicle is currently
located after data patching is over, and those data belonging to
each of the areas are filtered again through an additional clipping
process.
[0088] The following example corresponds to FIG. 4B, and
illustrates how the areas are patched together to give RGI data
based on the present location of the vehicle as it moves to another
area ). As noted above, backup areas are those areas selected prior
to an area where the vehicle is currently located, a reference area
is where the vehicle is currently located and a new area is an area
newly added based upon it including RGI data and being within index
.+-.1 of the present area. The parameter "n" illustrates how many
areas have been searched and included.
[0089] Location a: id 13, n=1, in which the vehicle travels along a
route in the order of 13, 14 and 10. [0090] reference area: 13 (0,
0) [0091] new area: 13 (0, 0), 14 (1, 0) and 10 (1, 1)
[0092] Location b: id 14, n=4, in which the vehicle travels along a
route in the order of (13, 14 and 10) (all previously searched, as
designated by the parenthesis), 11 and 10'. [0093] backup area: 13
(-1, 0) and 10 (0, 1) [0094] reference area: 14 (0, 0) [0095] new
area: 11 (1, 1) and 10' (0, 1)
[0096] c: id 10, n=6, in which the vehicle travels along a route in
the order of (13, 14, 10, 11 and 10'), 6 and 7. [0097] backup area:
13 (-1, -1), 14 (-1, 0) and 11 (1, 0) [0098] reference area: 10 (0,
0) and 10' (0, 0) [0099] new area: 6 (1, 0) and 7 (1, 1)
[0100] d: id 11, n=8, in which the vehicle travels along a route in
the order of (13, 14, 10, 11, 10', 6 and 7) and 8. [0101] backup
area: 13 (-2, -1), 14 (-1, -1), 10 (-1, 0), 10' (-1, 0), 6 (-1, 1)
and 7 (0, 1) [0102] reference area: 11 (0, 0) [0103] new area: 8
(1, 1)
[0104] e: id 6, n=9, in which the vehicle travels along a route in
the order of (13, 14, 10, 11, 10', 6, 7 and 8). [0105] backup area:
13 (-1, -2), 14 (0, -2), 10 (0, -1), 10' (0, -1) and 7 (1, 0)
[0106] reference area: 6 (0, 0) [0107] new area: (none)
[0108] f: id 7, n=9 in which the vehicle travels along a route in
the order of (13, 14, 10, 11, 10', 6, 7 and 8) and 4. [0109] backup
area: 13 (-2, -2), 14 (-1, -2), 10 (-1, -1), 10' (-1, -1), 6 (-1,
0) and 8 (1, 0) [0110] reference area: 7 (0, 0) [0111] new area: 4
(1, 1)
[0112] g: id 8 [0113] backup area: 13 (-3, -2), 14 (-2, -2), 10
(-2, -1), 10' (-2, -1), 6 (-2, 0) and 7 (-1, 0) [0114] reference
area: 8 (0, 0) [0115] new area: (none)
[0116] h: id 4 [0117] backup area: 13 (-3, -3), 14 (-2, -3), 10
(-2, -2), 10' (-2, -2), 6 (-2, -1), 7 (-1, -1) and 8 (0, -1) [0118]
reference area: 4 (0, 0) [0119] new area: (none)
[0120] FIG. 5 is a flowchart illustrating an operational process
for patching initial RGI data during map matching of the ITS
terminal in FIG. 2 (step 32C).
[0121] When the vehicle moves as shown in FIG. 4B, the ITS terminal
searches for an RGI area corresponding to id 13 in step 51. In step
51, the ITS terminal judges whether the index is within .+-.1 of
the reference index of the present location. Since the vehicle is
in the reference area 13 (0, 0), the index is within .+-.1 of the
reference index of the present location. Therefore, in step 53, the
RGI area corresponding to id 13 is added to the area list. In step
54, it is judged whether the RGI area corresponding to id 13 is
identical with the present location. If identical, an RGI area
corresponding to id 14 is searched in step 55. Judging whether the
indices are within .+-.1 of the reference index of the present
location in step 56, they are in a reference area 13 (0, 0) and a
new area 14 (1, 0) and thus within .+-.1 of the reference index of
the present location. Therefore, in step 57, an RGI area
corresponding to id 14 is added to the area list. Returning to step
55, a next RGI area, i.e., an RGI area corresponding to id 10 is
searched. Judging whether the indices are within .+-.1 of the
reference index of the present location in step 56, they are in a
reference area 13 (0, 0), new areas 14 (1, 0) and 10 (1, 1) and
thus within .+-.1 of the reference index of the present location.
Therefore, in step 57, an RGI area corresponding to id 10 is added
to the area list. In FIG. 4B, the first data patch is about 13, 14
and 10, the process proceeds no more.
[0122] If it is judged that the area is not identical with the
present location in step 54, step 58 judges whether a next RGI area
is the last RGI area, i.e., includes the destination. If not, the
process returns to step 51 in order to search a next RGI area. In
FIG. 4B, the next RGI area is 14. If the next RGI area is also
different from the last RGI area, the above process is repeated. In
the worst situation, the process is repeated to search until the
last RGI area or id 4.
[0123] Thus, the vehicle only selects and processes RGI data for
areas based on the current location of the vehicle and its
immediate surroundings for the initial route. Location of the
vehicle with respect to the RGI data under consideration is used to
perform route guidance via map matching. By using a focused amount
of RGI data for route guidance and map matching, processing loads
are reduced and speed is increased. If all received RGI data were
to be searched and used in map matching, a large processing load is
incurred.
[0124] FIG. 6 is a flowchart illustrating an operational process
for patching subsequent RGI data during map matching of the ITS
terminal shown in FIG. 2.
[0125] In step 61, indices of the existing searched areas having
ids 13, 14 and 10 will be changed, in which backup areas are 13
(-1, 0) and 14 (0, 0), 10 (0, +1).
[0126] In step 62, the ITS terminal searches a next RGI area.
[0127] In step 63, the ITS terminal judges whether the
corresponding RGI area is within .+-.1 of the reference index of
the present location. If the index of the corresponding RGI area is
within .+-.1, the ITS terminal adds the corresponding RGI area to
the area list in step 64, and then returns to step 62. RGI areas
are added to the area list in this manner owing to variation in
reference.
[0128] In the meantime, the process terminates if the area is not
within .+-.1 of the reference index of the present location.
[0129] Referring to FIG. 2 again, the route is guided in step
33C.
[0130] The ITS terminal generates information about next route
guidance from matched road information and RGI data. And, the ITS
terminal performs map matching by information of a link and a node
in the selected RGI area to calculate a road where the vehicle is
currently located. That is, ITS terminal generates turning
information such as lateral turning and distance left to a next
route guidance point.
[0131] According to the present invention as set forth above, the
map matching and route guidance data are obtained using the
multi-route and detailed intersection information added to the
specific format of RGI data so that re-accessing the information
center can be minimized after departure of a user from a route by
intention or mistake, as well as indicating beforehand, the
detailed intersection information overcoming drawbacks that this
system does not install a map so as to minimize telephone charges
required for accessing the information center. This also allows a
system body to efficiently perform the navigation service even
without a map database. The system body can optimize a policy of
treating the RGI data so as to reduce system load while enhancing
performance.
[0132] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions can be made without departing from the scope and
spirit of the invention. It is intended that the scope of the
present invention is not be restricted to the foregoing embodiment
of the invention but shall be defined by the following claims and
equivalents thereof.
* * * * *